"As long as it's not unfair to one party — but if there's a dispute on that contract, then a longer term could be deemed to be an unfair contract clause," Ms Carnell said.

"So there doesn't need to be the contract police."

She explained that those disputes would be mediated in the court system, "or alternatively, places like my office".

"[My office] handles business-to-business disputes, so there's a number of ways it can be done," she said.

"But fundamentally we've got to put a line in the sand — if large, multinational, billion-dollar companies can continue to push out their payment times for small business, it stops the economy growing.

"Small businesses can't invest in their businesses, they can't employ if they don't have cash flow.

"Cash flow is the fuel of the engine room in our economy, so we've got to get cash flow moving for small business."

'We need to name and shame'

Ms Carnell also recommended companies should have to publicly report their performances.

"We think that naming and shaming is a good idea," she said.

"And you can't do that unless we've got actual publication of what's happening with payment terms and times — they've done this in the UK.

"We're talking about the top 100 companies in Australia being required to report twice a year on their payment times, their terms and how they've delivered against those.

"We will be starting the process of setting up a national transparency register website to encourage this to happen."

Ms Carnell said she would be disappointed if the Government were to not take the recommendations seriously.

"The Government, and for that matter the Opposition and all parts of Parliament, continue to talk about the small business sector as being the engine room of the economy," she said.